perf evlist: Only open events on CPUs an evsel permits
In systems with heterogeneous CPU PMUs, it's possible for each evsel to cover a distinct set of CPUs, and hence the cpu_map associated with each evsel may have a distinct idx<->id mapping. Any of these may be distinct from the evlist's cpu map. Events can be tied to the same fd so long as they use the same per-cpu ringbuffer (i.e. so long as they are on the same CPU). To acquire the correct FDs, we must compare the Linux logical IDs rather than the evsel or evlist indices. This path adds logic to perf_evlist__mmap_per_evsel to handle this, translating IDs as required. As PMUs may cover a subset of CPUs from the evlist, we skip the CPUs a PMU cannot handle. Without this patch, perf record may try to mmap erroneous FDs on heterogeneous systems, and will bail out early rather than running the workload. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1473330112-28528-7-git-send-email-mark.rutland@arm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Please register or sign in to comment